Rain calms California freeway wildfire

A wildfire that swept across a busy California freeway and sent people running for their lives has been calmed by rain, allowing some crews to be shifted to another blaze that forced hundreds of campers to evacuate.

The rain and lower temperatures helped pacify the fire that had burned over Interstate 15 in Cajon Pass, a mountainous area 88.5 kilometres northeast of Los Angeles.

The fire destroyed 20 vehicles on the freeway linking Southern California and Las Vegas before burning three homes and 44 more vehicles in the community of Baldy Mesa.

The fire was five per cent contained after charring 14.24 sq km.

Firefighters turned their attention to protecting some 700 homes in the Baldy Mesa area, where about 2800 people remained evacuated and nearly three dozen spent the night at a temporary shelter.

US Forest Service spokeswoman Carol Underhill said rain was helping firefighters and the fire wasn't growing.

The fire had sparked sheer chaos when it began next to Interstate 15.

Fuelled by 64 km/h winds, the blaze raced uphill and onto the traffic-clogged freeway, temporarily trapping hundreds of people amid a cauldron of smoke, flames and ash.

Amazingly, only two people were injured. Both suffered minor smoke inhalation, authorities said, but declined medical attention.